Pen stand base



FIG. 1 is a top plan view of a pen stand base showing my new design;

FIG. 2 is a front elevational view, the opposite side being a mirror image thereof;

FIG. 3 is a bottom plan view; and

FIG. 4 is a side elevational view, the opposite side being a mirror image thereof.

The rear elevational view of the pen stand base shown in FIGS. 1 to 4 is identical to the front elevational view thereof. The side elevational view of the pen stand base which is not illustrated is identical to the side elevational view which is illustrated. 

The ornamental design for a pen stand base, as shown and described. 